Coin-controlled telephone system in which tariff rates for telephone calls are audibly transmitted automatically to a calling subscriber



2,676,209 ARIFF RATES l2 Sheets-Sheet l Aprll 20, 1954 A. E. JOEL, JR

COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH T FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY To A CALLING sUBscRrB Filed sept. 1, 1949 ill.

lApril 20, 1954 A. E 2,676,209

v JOEL, JR COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY TO A CALLING SUBSCRIBER Filed Sept. l, 1949 l2 Sheets-Sheet 2 /NVEA/ro'n 4,4. E. JOEL, JR.

A7' TOR/VE Y FIG. 2

APHl 20, 1954 A. E. JOEL, JR 2,676,209-

COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY TO A CALLING SUBSCRIBER Filed Sept. l, 1949 l2 Sheets-Sheet 5 sai-EF ITIIHQ ATTORNEY April 20, 1954 A. E. JOEL, JR 2,676,209

com-coNTRoLLED TELEPHONE SYSTEM 1N WHICH TARIFF RATES RoR TELEPHONE cALLs ARE AUDIBLY TRANSMITTED AuToMA'rIcALLY To A CALLING sUEscRIBER Filed Sept. l. 1949 12 Sheets-Sheet 4 /NVENTOR A. E. JOEL, JR

A7' TORNE V Apnl 20, 1954 r A. E. JOEL, JR 2,676,209

COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY TO A CALLING SUBSCRIBER Filed Sept. 1, 1949 12 Sheets-Sheet 5 A. E JOEL, JR. d 7&4(

Ar TOR/vir A. E. JOEL, JR COIN-CONTROLLED TELEPHONE SYSTEM IN WHI Aprll 20, 1954 2,676,209

CH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY To A CALLING sUBsCRIBER 12 Sheets-Sheet 6 Filed Sept. l, `1949 /NVENTOR A. E. JOEL, JR.

W5 gi@ ATTORNEY April 20, 1954 A. E. JOEL, JR 2,676,209

COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY TO A CALLING SUBSCRIBER Filed Sept. l, 1949 12`Sheets-Sheet 7 v /NVE/vron A. E. JOEL, JR.

.9x/4 v/M AT TORNEK Apnl 20, 1954 A. E. JOEL, JR 2,676,209

COIN-CONTROLLED TELEPHCNE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY To A CALLING `SUBSCRIBER Filed sept. 1, 1949 y lasheets-sheet s /NVENTOR A. E. JOEL, JR.

ATTORNEY April 20, 1954 A. E. JOEL, 1R 2,676,209

COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY TO A CALLING SUBSCRIBER 12 Sheets-Sheet 9 Filed Sept. l, 1949 m .um

ATTORNEY plll 20, 1954 A, E, JOEL, JR 2,676,209

COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY TO A CALLING SUBSCRIBER Filed sept. 1, 1949 Y 12 sheets-sheet 1o Y ACR A 7' TOR/VE V A. E. JOEL, JR COIN-CONTROLLED TELEPHONE SYSTEM IN April 20, 1954 2,676,209

WHICH TARIFF RATES FOR TELEPHONE: CALLS ARE AUDIBLY TRANSMITTED AUTOMATICALLY To A CALLING sUBsCRIBER l2 Sheets-Sheet l1 Filed Sept. l. 1949 By A. E. JOEL, JR.

ATTORNEY Apnl 20, 1954 A. E. JOEL, .mv 2,676,209

com-coNTRoLLED TELEPHONE SYSTEM 1N WHICH TARIFF RATES FOR TELEPHONE CALLS ARE AUDIBLY TRNSMITTED AUTOMATICALLY To A CALLING SUBSCRIBER A T TORNE Y Patented Apr. 20, 1954l COIN-CONTROLLED TELEPHONE SYSTEM IN WHICH TARIFE RATES FOR TELEPHONE CALLS AREAUDIBLY TRANSMITTED AU- TOMATICALLY TO A CALLING SCRIBER SUB- Amos E. Joel, Jr., New York, N. Y.,kassignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application september 1, 1949, seria1N0.113,642

19 Claims.

, 1 This invention relates to telephone systems and more particularly to automatic telephone systems in which ca-lls originating at dial stations equipped with coin boxes are charged `against thel calling party through the collection of deposited coins or tokens.

In C. E. Brooks et al. Patent 2,357,576 of September 5, 1944,-there is disclosed a system'of the general character defined above which embodies improvements over dial switching telephone systems of the usual type, and which serves to reduce to a minimum the services of an operator in supervising toll calls for the purpose of collecting and refunding coins or tokens deposited by the calling party in accordance with the tariff rates for initial and overtime periods of conversation on such calls. In the system 'of the aforenoted patent all short haul, low tariff calls from coin box lines are directed to a trunk outgoing to a tandem oiiice, such trunks having separate appearances in the banks of district or office selectors and separate lamp and jack appearances at the A operators switchboard for each tariff rate. On the initiation of a call from a coin box line the calling party first deposits a coin to enable the call to be started and after receiving the usual dial tone proceeds to dial the directory number of the Wanted line. The oice code and numerical digits of the line number thus dialed are registered in the sender of the calling oice and in accordance with the oce code digits registered, a district and, if required, an oice selector are set to select an idle trunk extending to a tandem ofce. The oflice code determines over which one of its district selector or cnice selector appearances the tandem trunk will be seized, that is, the appearance which is allocatedto the proper tariff rate for the desired connection.

At the tandem oiice, upon seizure of the trunk, a connection is established with an idle tandem sender, following which the sender of the originating oce is signaled to transferthe oiiice code and numerical digit registrations of the wanted line number to registers of the tandem sender. After the number has been completely transferred, the proper charge rate lamp corre` ing person to deposit coins in lthe Aamount indi',`

cated by the charge rate lamp Which lWas lightedV and after hearing the deposit of such coins, disconnects lier cord circuit from the jack. When she disconnects her cord circuit from the jack the tandem sender is signaled to proceed to control the completion of the connection te the wanted line in accordance with the digit information registered therein.

When the called subscriber answers, the timing of thecall is initiated and after 4'1/2 minutes the deposited coins are collected. After minutes the proper charge rate lampis iiashed to indicate to the operator that an overtime interval has been reached. The operator again plugs a cord circuit into the'jack associated With the flashing lamp and directs the calling person to signal her When he is through talking. YIn most cases the subscriber will elect to terminate the conversation at once. If he does not elect to do so, however, the operator leaves the plug ofthe cord circuit in the trunk jack, Writes a ticket and handlestlie call in the Well-known manner.`

It is apparent that, While the services of the operator on calls of the type described are considerably reduced over those required' of a-n operator under usual practice, such services are not entirely eliminated since the continued' supervision of the operator is required during any of the overtime periods during which conversation is continued, and since it is Anecessary also Yfor the operator to come in on the connection'before -it is completed to the desired ydestination in order to request the calling party t0 deposite coins in accordance with the tariff rate prescribed for the initial period of conversation.

It is the object of the present invention to substantially eliminate vthe need for operators' on toll callsl originated at coin box stations, and to otherwise improve coin controlled telephone communication systems to `the extent that the acts heretofore performed by an operator on such toll calls in requesting for, collecting, and refunding coins or tokens are performed automatically.

In accordance With -a feature of the invention this object is attained through the medium .of apparatus which functions automatically vto transmit to a calling party at a coin box station a predetermined pronouncement indicative of the tariff rate prescribed for the initial period of conversation on a toll connection initiated at the coin box station. More particularly, a plurality of vmessage bearing devices, Vsuch as mag-.- netic tape type, telegraphones, are provided, each corresponding to a particular set of bank terminais in which a tanden trunk terminates,and

each bearing a request pronouncement for the deposit of coins in the value of the tariff rate determined by its corresponding set of bank terminals over which the trunk is seized in response to the dialing of the telephone designation of a particular called line.

A further feature of the invention resides in the use of coin controlled signal generators at the coin box station which function to identify each coin deposited thereat by a distinctive combination of two frequencies, and of means selectively responsive to the frequencies generated incident to the deposit of the coins for registering such coin deposits. A related feature contemplates the use of cooperating selector switches and a coin adding and register circuit which function automatically to totalize the values of the coins deposited at a coin box station; to check the amount deposited for the initial period of conversation against the prescribed tari rate for such period; and to control the completion of an initiated call only when the totalized value of the deposited coins corresponds with the prescribed tari rate.

Another feature of the invention provides means under control of the totalizing selector switches which functions to transfer' the initiated call to an operator in the event the calling party fails to deposit the amount of tariff indicated by the telegraphone pronouncement automatically transmitted to the calling station on a toll call originated thereat, and which functions also to automatically advise the connected operator of the prescribed tariif rate.

A still further feature provides means whereby, after the initial period of conversation has terminated, the calling subscriber is automatically requested to deposit additional coins for overtime service and whereby the value of such coins, if deposited, is registered and checked against the tariii` rate prescribed for such overtime service.

Still another feature of the invention resides in a timing-out circuit which functions, a predetermined interval of time after a coin deposit has been requested and has not been made, to automatically bring in an operator on the connection.

These and other features of the invention will be readily understood from the following description when read with reference to the accompanying drawings, in which:

Fig. 1 shows, in the upper position thereof, a coin box line terminating in a panel type ofce, a line iinder, district selector, oice selector and sender of which are schematically illustrated; shows, in the lower portion thereof a coin box line terminating in an oirlce of the well-known crossbar type, the line switch district and oice selector frames, sender link switch frame, sender and marker of which are indicated by suitably labeled boxes; shows, in the right portion thereof the selector switch appearances of the outgoing end of a trunk extending from the originating oce to a tandem oiiice; and shows schematically, at the extreme left, the coin operated signal generators associated with each of the coin box lines illustrated;

Figs. 2, 4 and 5 taken together show the outgoing end of a tandem trunk;

Fig. 3 shows, in the upper portion thereof, the tandem oiiice end. of the tandem trunk terminating in a tandem district selector, and, in the lower portion thereof, such portions of a tandem sender associable with the trunk as are necessary to an understanding of the invention;

Fig. 6 illustrates diagrammatically, one of a number of link circuits to which the tandem trunks have access and which function, when seized, to extend a trunk to a common coin controlled pronouncement circuit;

Fig. 7 illustrates diagrammatically the common coin controlled pronouncement circuit; a timing-out circuit; and a plurality of jacks located at a monitoring operators position;

Fig. 8 shows diagrammatically a coin register and adding circuit which functions under control of an alternating-current signal receiver, Figs. 10 and 11, to recognize and register the deposit of nickels, dimes and quarters at a calling station and to condition the totalizing selectors, Fig. 9, accordingly, so as to enable them to totalize the values of the coins deposited at the calling station and to check such deposit against the tariif rate prescribed for initial and overtime periods of conversation on a call originated at a coin box station;

Fig. 9 illustrates diagrammatically the totalizing selectors which function to totalise the coins deposited at a calling station; to check the total against the prescribed tariff rates; and to direct the initiated call to a monitoring operators position in the event the amount totalized does not check with the required tariff rates, or to permit the call to advance to completion when the value of the deposited coins checks with the prescribed tariii rates;

Figs. 10 and 11 constitute an alternating-current signal receiver which functions to detect the frequencies generated at the coin box station incident to the deposit of coins thereat and to transmit such information to the coin register and adding circuit of Fig. 8;

Fig. 12 is a chartV showing how the several figures of the drawings should be arranged to illustrate a complete system embodying the invention; and

Figs. 13 and 14 are partial views of a standard coin box modied to embody the coin controlled signal generators located at the coin box station.

Referring to the drawings, the apparatus of the originating panel type oice X, disclose schematically in the upper portion of Fig. 1, may be of the well-known type such as is disclosed, for example, in Patent No. 1,862,549, granted June 14, 1932, to R. Raymond and W. J. Scully, and the apparatus of the originating cross-bar type office Y, disclosed schematically in the lower portion of Fig. l may be of the wellknown type such as is disclosed, for example, in Patent No. 2,093,117 granted September 14, 1937, to W. W. Carpenter. The interoiiice tandem trunk may be used in common by a panel and a cross-bar office if they are in the same building, by strapping both the (p) and (c) cross-connections, but if such oiices are not in the same building it is to be understood that a separate group of tandem trunks would extend from each oflice to the tandem office, and that a trunk when outgoing from the panel oftlce would be connected by the cross-connections (p) to selector bank appearances in such ofce and when outgoing from the cross-bar office would be connected by the cross-connections (c) to cross-bar switch appearances in such office. The apparatus of the tandem oiiice shown schematically in Fig. 3 may be of the general type disclosed in Patent No. 1,840,132 granted January 5, 1932, to T. H. Roberts, the tandem sender, however, being slightly modied as will be presentlydescribed. The interrupters 5l) I, 502 and 503 of Fig. 5 form a part of a motor-driven timer 5501 of: the. .general type disclosed in Patent No. 2,112,375 granted March 28, 1938, to E. D. Mead. The interrupters are arranged to be clutched to the shaft of the driving motor by the operation of clutch magnet 504. Interrupters 505 to- H, inclusive, are miscellaneous power-driven interrupters on the interrupter frame of the originating office.

An alternating-current impulse receiving circuit ACR is disclosed in Figs. and ll. This circuit is a substantial duplicate of the circuit shown in Patent No. 2,332,912 granted to G. Hecht, A. A. Lundstrom and E. R. rlaylor on October 26, 1943. This receiver circuit will be described in suiiicient detail inthe presen-t application to insure a clear understanding of its operation. The circuit is, however, described in a more comprehensive manner `in `the aforenoted Patent No. 2,332,912.

The equipment illustrated in Fig. 7 is located at the originating ofce. 1t consists principally of a plurality of magnetic vtape-type telegraphones, two of Which are illustrated diagraininatically at 26 and '52! a timing-out circuit TS, a hybrid coil H, and a plurality of jack terminations. The purpose and functioning of this apparatus will appear from the detailed description to fol low. Suffice it to say at this time, that the 0peration of the equipment shown in Fig. 'I is initiated when any one of a group of relays, such as relay i12 is operated incident to the seizure of the tandem trunk by Way of a corresponding set of bank terminals 191, Ict. rlhere are as many relays '152, iSi), etc., as there are terminal appearances of the tandem trunk at the originating cnice. For each relay H2, 15b, etc., and therefore, for each bank appearance l'i, ltd, etc., of Y the tandem trunk, there is one telegraphone such as TEG, 'i2 i, etc. The telegraphone for each bank appearance carries a pronouncement which indicates the tari rate prescribed for initial and overtime periods of conversation for aA call originated at a coin box station and extended over the corresponding bank appearance of the tandem trunk. Through the medium of the hybrid coil ii the pronouncement carried by the telegraphone selectively seized, incident tothe initiation of a call at a coin box station, is transmittedv to the calling station and, under particular circumstances which will be fully described hereinafter, to the monitoring operators position. A single proncuncernentl device serves both the initial and overtime periods since, in the present system, it is assumed that the tarii rate in eachv case is the saine. The request pronouncement may be given any suitable wording, for example, it may consist or" the phrase Please deposit ten cents for ve minutes.

The link circuit illustrated in Fig. 6 is common to a plurality of tandem trunks and functions incident to the operation of a trunk preference relay, such as relay EM and the resulting 4operation ci a corresponding trunk connector relay 626 and a coin control connector relay, such as relay to extend the trunir to the pronouncement circuit, Fig. 7.

The coin register and adding circuit of Fig. 8, as illustrated, comprises three groups of register reiays such as CII, R51, Rini, Rii and All, C12, R52, RISA, R252' and A12, and C13, R53, Rits, R253 andl A13. The operation of a relayy CIi, CI? or C13. determines which of the three registers is to function to register therst. deposit of a coin the circuit is so arranged' that relay Cli will operate to render'the first'` register avail coin box structure'.

able to register the first kcoin deposih relay SI2 will. operate to render theJ second register avail,- able to register. the. second coin deposited, etc. The relays R51, R52 andiRES operate to recognize thel deposit of nickels; relayRiBfl, R102 and RI d3 to recognize the deposit.. of dimes;- and relays R25'll, R252 'andRES to'recognize the deposit of quarters.v Relays AII, A12 and A13 serve to transmit the information registered by' thev coin register and adding circuit to the totalrin'gV selectors; T and AIS of Fig. 9- Relays 821i', 82 Iv and 532i which appear aty the Vupper right' of Fig. 8 function te. control the advance of the initiated call. toits desired. destination, or to' a monitoring operator as; conditionsvrequi're.

The-.coin signalsv are generated at. the: coin box station through the medium. lof' three sets of. vibratable reeds` located in such positions vrelative to the slots into which the. variouscoins are deposited .in the coin box that: eachcoin, its passage through its .respective 4slot contacts a. pair of reeds 'causing them to vibrate. Each pair of reeds, When. actuated` by a. coin deposited by a calling subscriber, vibrates within a. coil lsuch as the coils` diagranmiatically' illustrated at the left of Fig. l..r Each coil and its: associated pair of reeds are supported Within afsuitable housing and the housings are mounted on a` bracket in the As illustrated, the three generating coils are connected in series across the coin boa line' and, during the course of a connection involving the coin box line, are energized by current from the. central office. battery. Each f pair of reeds has one reed.- tuned to vibrate at a frequency f and the remaining reed of each set is tuned to vibrate at a different frequency a., b or d.. Thus, Whenever a coin is. deposited in the coin chute the corresponding reeds are vibrated to generate a double frequency current, one of the frequencies in each case being the frequency In. the .instant applicatiom the reed sets are designed so that' the pair of' reeds associated with the nickel. chute will, when vibrated, generate frequencies a, f; the pair of reeds associated with the dime chute will,v when vibrated generate frequencies b., j; and the pair of reeds associated with the quarter chute: will, .when Vibrated, generate. frequencies d, f. These frequencies, as will appear from a later description, serve to selectively operate, through the alternating-current signal receiver ACR, Figs. lo: and 11, relays i ici), i Mii and l 02.' which control the operation of the so-ealled nickel, dime: and quarter relays of the coin register and; adding circuit, Fig. 8.

The. selector'switches AIS andT of Fig.y .9v which function. to totalize and, check the value of the coins. deposited'. ata coin box station are oi? the Well-known step-by-step selector switch type, each. having its. own stepping magnet. The switch AIS is provided withl ve terminal. banks or arcs AISI; AES-2 A163., AIS and. .AISt Whereas the switch T is provided Withfour arcs Ti, T2, T3 and '.li'.

'Ehet'arc TS2-of svvitch-4 T is provided with a. plurality of. terminals tol each. one-of which, except the. rstispermanently connected a charge lead, or. conductor, sothat each such terminal corresponds to a. particular tai-irlv rate, the second terminal being allocated to a ve-'cent charge, the third to a ten-cent charge, the fourth to a fifteen-cent charge, and so on. Upon the initi ation of Aa toll call at a coin boxA station a charge lead,` such as 6'3-'9 forV example, is' marked so as to mark a corresponding terminal of the arm T3 of' switch Tv and to thereby inform the switches 7, that an amount corresponding to the charge allocated to the particular marked terminal must be deposited by the calling subscriber.

The terminals of arc Ti of switch T are strapped to corresponding terminals of arc AISl ci the switch AIS whereas the terminals of arc T2 of switch T are strapped to the terminals of arcs AIS2, AIS3 and AISd as illustrated. The brushes of arcs A182, AIS3 and AISA are out through to the controls of the so-called nickel, dime and quarter relays, such as REL Ridi and REM, for example, whenever a relay All, A12 or AIS is operated so that if any of the said nickel, dime and quarter relays is operated, the first terminal of the corresponding arc of switch AIS is marked and such marking determines the number of steps to be taken by the selector switch T. It will be observed that the first terminal of arc AIS2, which is rendered operative when a so-called nickel relay, such as R! for example, is operated, is connected to the first (off-normal) terminal of the arc T2 of switch T; that the iirst terminal of arc AISiof switch AIS corresponding to a so-called dime relay, such as Riti for example, is strapped to the second (olinormal) terminal of the arc T2 of switch T; and that the iirst terminal of arc AIS, of switch AIS is strapped to the fth (oli-normal) terminal of are T2 of switch T. Obviously, therefore, when the selector T is stepped around in search or a marked terminal on its arc T2, it will advance one step if the are AIS2 of switch AIS is marked to indicate the deposit of a nickel; will advance two steps if the arc AISS of switch AIS is marked to indicate the deposit of a dime; and will advance live steps if the are AISd of switch AIS is marked to indicate the deposit of a quarter. Thus, the selector T will advance one, two, or live steps depending upon whether the rst, second or iifth terminal of its arc T2 is marked through the terminals of arcs AIS2, AISS or AISi, respectively, of switch AIS, which terminals, in turn, are marked as a consequence of the operation of relay REI, R|0| or R252, respectively, which occurs when a nickel, dime or quarter, respectively, is deposited at the coin box station. If the correct sum has been deposited by the calling subscriber, the switches AIS and 'I will operate in such a manner that the brush of arc T3 of switch T will come to rest upon the terminal thereof marked by a charge lead, such as conductor S for example, and the initiated call will be allowed to advance. If the brush of arc T comes to rest upon an unmarked terminal indicating a deposit of an incorrect amount of tari by the calling subscriber the connection will be directed to a monitoring operator as will be described more fully hereinafter.

It will be observed also that the terminal strappings between arc T2 of switch T and of arcs AIS2, A153 and AISQ of switch AIS are so arranged that it makes no diierence what coins are used in payment for the toll charge so long as their total value corresponds to the tariff rate prescribed. For example, a toll charge of twenty-five cents may be paid with ve nickels, with one nickel and two dimes, or with three nickels and one dime, and the switches AIS and T will function to check the total deposit against the prescribed tarii rate.

Arc Td of switch T and arc AIS of switch AIS function to restore their respective switches to normal, and tc thereafter transmit the signal which permits the initiated call to be advanced 8. to completion, or the signal which routes the call to a monitoring operator.

Initiation of call into ten-cent toll area It will be assumed that a person at the substation |00 of the coin box line which terminates in the panel type oice X, desiring a toll connection, deposits a nickel in the nickel coin slot of the coin box apparatus schematically shown at |ll| in Fig. 1, and in greater detail in Figs. 13 and 14, and upon removing the substation receiver from the switchhook, becomes connected by the line iinder |02, over the line iinder-district selector trunk |03 and the usual sender link circuit (not shown), with an idle sender E06 in the manner fully described in the Patent No. 1,862,549, hereinbefore referred to. When the calling line becomes connected with the sender the usual dial tone is transmitted from the sender to appraise the calling person that he may proceed to dial the digits of the desired line number. It will be assumed further that a number is dialed, the oiiice code digits of which indicate that a ten-cent charge is required for the initial period of conversation. In accordance with the present invention, al1 toll calls to be terminated in the nearby toll area, such, for example, as calls involving ten-cent, hitech-cent, etc., initial charges, are routed over special tandem trunks to a tandem office through which they are then completed. Therefore, in response to the registration of the cnice ycode digits indicative of the fact that the call is to be extended into a ten-cent zone or" the exchange area, the sender it@ proceeds to control the setting' of the district selector IE5 and the oiiice selector we to select an idle trunk extending to the tandem office. It will be assumed that the trunk disclosed in Figs. 1, 2, 3, 4 and 5 is idle and is seized therefore by thtegi'iice selector |06 over the bank terminal se It will be noted that this trunk has two terminal bank appearances in the switch bank of cnice selector |06, one of which, |07, is allocated for seizure on all toll calls for which the initial charge rate is ten cents and the other of which, E08, is allocated for seizure on all toll calls for which the initial charge rate is fifteen cents. It is obvious that if it should be desired to enable connections to be established by dial control from lcoin box lines to subscribers" lines terminating 1n more remote oiiices of the exchange area, other appearances of the tandem trunk in banks of selector switches may be provided, allocated, for example, to calls for which the initial charge rate might be twenty cents, twenty-nyc cents, etc.

When the tandem trunk is seized, ground is applied over the sleeve brush and sleeve terminal H0 of the trunk in well-known manner and thence to the sleeve terminal of all other bank appearances of the trunk and multiples thereof to mark the trunk busy. When all dialed digits have been registered in the sender 04, a circuit is established from battery through the right winding of relay 300 and over contacts ci cam 30| in the incoming end of the tandem trunk of the tandem oflice, over trunk conductor 382, the No. 8 back contacts of relay 2de, the No. 5 back contacts of relay 26|, through the upper winding of polarized relay 202, the No. 7 back contacts of relay 203, the No. 8 back contacts of relay 2,04, conductor 205, through the upper winding of relay the No. 6 back contacts oi relay I2, over the tip bank terminal of terminal set |01, tip brushes of selectors |08 and i05, conyil) tacts of cam II3 at the district selector |05, thence through. the windings of relays in the sender |04, returning over contacts of cam H4, ring brushes or" selectors I05 and |06, ring bank terminal of terminal set I01, the No. 2 back contacts oi relay H2, conductor 206, the No. 2 back contacts of relay 201i, the No. l back contacts of relay 203, through the lower winding of polarized relay 202, the No. 3 backV contacts of relay 20L the No. 2 back contacts. of relay 200., trunk conductor 303, contacts of cam 304 to ground through the left winding of relay 300. Relays III and 300 operate in this circuit, relay 300 functioning to cause the association of a tandem sender with the incoming end of the tandem trunk, and relay Hi, upon operating, establishing a locking circuit for itself extending from battery through the winding of relay I I5, through the lower winding and contacts of relay III, conductor H0, the No. 5 normal contacts of relay 203, conductor I I1, sleeve terminal IIO, brush 109 to ground in the oice selector.

Relay i i5 operates in this locking circuit, locks over its upper front contacts to ground on conductcr i I5; connects the trunk conductors 265 and 2te over its inner upper and lower contacts to the tip and ring terminals of the terminal set i? independently of the contacts of relay H2; and establishes a circuit for relay I l2 which may be traced from grounded batteryA through its Winding, over the auxiliary inner iront contacts of relay H to ground. Relay II2 upon operating, at its lower back contacts, disconnects the multiples of all unused appearances of the trunk. These operations take place while the circuits at the tandem office are recognizing the closure, advancing the trunk and link circuits and selecting an idle sender.

Upon the seizure of the tandem sender, a pulse receiving circuit is established between the original sender and the tandem sender, schematically disclosed in the lower portion of Fig. 3, which extends, as previously traced, from the sender E00 to trunk conductor 302, thence over contacts of cam 305, back contacts of relay B, upper normal contacts of relay 301, upper back contacts of relay 3&3, serially through the windings of impulse responsive relays 309, 3I0 and 3II, lower back contacts of relay 308, inner lower normal contacts of relay 301, contacts of relay SI2, contacts of cam 3I3, trunk conductor 303 and thence as traced to the originating sender Ict. in response to the closure of this circuit the originating sender proceeds to transmit codes of impulses for the purpose of transferring the called line designation digits from its registers to registers of the tandem sender. At the end of the last code impulse transmitted for the units digit series, with relay 3M operated, relay 308 operates in a circuit from battery through its winding, over the upper contacts of relay 3M, the lower back contacts of relay SI5, the back contacts of relay 300 to ground. With relay 300 operated, the impulse receiving circuit is prepared for the reception of the iinal positive inipulse transmitted from the sender I04 which circuit extends, as previously traced, over the upper normal contacts of relay 301, thence over the the impulse receiving circuit in parallel with the winding of relay 300. The winding of relay 300 is now connected reversely into the impulse receiving circuit whereby it is responsive to the receipt of the final heavy positive impulse and establishes a circuit from ground over its 'front contacts, over the upper normal contacts of relay 3l .1, through the Winding of relay 3HE and resistance SI1 to battery. Relay 3 I5 upon operating, locks over its inner upper alternate contacts to ground and prepares a circuit for relay till. Upon the termination of the inal heavy positive impulse when relay 309 releases, relay Bi energizes in a circuit from battery through resistance t i0, the winding of relay 3 I 8, the inner upper alternate contacts of relay 3I5 to ground. With relays 32,5 and 3I8 now both operated, a circuit is established for transfer relay 301 extending :roin grounded battery through its winding, over the lower front contacts of relay 308, the inner upper front contacts of relay 3M, the upper front contacts of relays 3I5 and 3i 8 to ground. With relay 301 operated, the circuit previously established by the operation oi relay 3M for relay 320 is opened at the lower back contacts of relay 301; relay 301 is locked over its lower front contacts to ground at the lower front contacts of relay 3M; and the circuit extending back to the originating sender is transferred from .the winding of relay 3,00 to the windings of relays 32I and 322, trunk conductor 302 being now extended over the contacts of cam 305, the back contacts of relay 300, the upper alternate contacts of relay 30'?, over the lower normal. contacts of relay 320, to battery through the winding of relay 32E, and trunk conductor 303 being now extended over contacts of cam 3 I3, the back contacts ci relay 3I2, the inner lower alternate contacts of relay 301, the upper normal contacts of relay 320, to ground through the Winding of relay 322.

At the outgoing end of the tandem trunk, polarized relay 202 operated its armature against its` left contact in response to the final heavy positive impulse, in turn causing the operation of relay 201 in a circuit from battery through its Y winding and the left contacts of relay 202, conupper iront contacts of relay 308, through the Y ductor 20d, to ground at the No. 3 contacts of relay H2. Relay 201 upon operating locks in a circuit. from battery through its winding, over its upper front contacts and the No. l back contacts of relay 200, to ground on conductor 208. At the end of the heavy positive impulse polarized relay 202 operates its armature against its right contact thereby opening the operating circuit of relay 201 and, with relay 201 locked operated, establishes a circuit from battery through the winding of relay 203, over the inner lower front contacts of relay 201 and the right contacts of relay 202 to ground on conductor 200. Relay 201 also connects ground on the No. 2 back contacts of relay 203 and its lower front contacts to peg count register conductor 203, and at its back contacts opens the timed release circuit. Relay 203 upon operating, locks over its No. d contacts to ground on conductor 20S; yopens the peg count register circuit at its No. .2 back contacts; at its No. 5 alternatecontacts establishes a new holding circuit for relay i I5 extending from conductor H3 over such contacts and conductor 2I0 to ground over the No. 3 back contacts oi relay 200; establishes an operating Acircuit yfor relay 20I extending from battery .through its winding, over the No. 6 contacts of relay 203, the No. '7 back contacts of relay2`00,

1 1 conductor 2 I, the inner upper back contacts of relay 500, conductor 2 |2 to ground over the inner lower normal contacts of relay 400; connects ground over its No. 2 front contacts and conductor i to the sleeve terminals of the trunk in cnice selectors of the panel office; connects ground over its No. 3 contacts and conductor ||8 to sleeve terminals of the trunk in the office switches of the cross-bar office in cases where the trunk is allocated to a cross-bar oiiice; at its Nos. 1 and 7 back contacts opens the circuit previously traced through the windings of polarized relay 202; extends trunk conductor 205 over the No. 8 back contacts of relay 204, the No. 7 iront contacts of relay 203, the No. 6 back contacts of relay 204, to ground through the lower winding of relay 2i 3; and extends trunk conductor 206 over the No. 2 back contacts of relay 204, the No. 1 front contacts of relay 203, and the No. 1

back contacts of relay 204 to battery through the a upper Winding of relay 2|3. Relay 20|, upon operating, disconnects the windings or polarized relay 202 from the trunk conductors S02 and 303 at its Nos. 3 and 5 back contacts, bridges, at its No. 6 contacts, the contacts of relay 500 included in its operating circuit; at its No. front contacts connects ground over the No. 8 back contacts of relay 200 and thence over the circuit traced to battery through the winding of relay 32| at the tandem sender, thereby causing the operation of relay 32| followed by the operation of relay 323, and connects ground over its No. a contacts, conductor 2|4, the No. 4 back contacts of relay 40|, conductor 402, to the armature of interrupter 501, which upon making its left contact completes the circuit of relay 5|2 over conductor 5|3, the No. 3 back contacts of relay 200, conductor 2 i5 to battery through the winding of relay 5|2. Relay 5|2 operates in this cir cuit to start a timing cycle to be later described. The operation of relay 323 at the tandem sender signals the sender that timing thereat must be suspended since there will be some delay before the calling subscriber is advised of the amount of toll to be deposited in the coin box and until the amount deposited is checked automatically. Relay 323 closes a circuit from ground over its upper front contacts and the upper back contacts of relay 324 to battery through the winding of relay 325. Relay 325 upon operating, causes the operation of relay 326 over an obvious circuit, which relay locks under the control of relay 32"! over its lower front contacts and the back contacts of relay 32's', and at its upper front contacts closes an obvious circuit for relay 02S. With relay 326 operated or unoperated, ground is connected over its contacts, the lower normal contacts of relay 329 and the back contacts of relay 325 to the back contacts of timing relay 330 to start the operation of timing relays 330 to 335 to time-out the tandem sender, but since relay 325 has been operated, this timing start circuit is not eiective and the timingout ci the sender is therefore delayed.

y When the originating sender has completed the transmission of the nal heavy positive impulse, it advances the sequence switch o the district selector |05 into the trunk closure position and the originating sender then becomes disconnected from the line under-district selector trunk |03 and is restored to normal. Relay 2|3 now operates in a circuit which may be traced from battery through its upper winding, the No. 1 back contacts of relay 204, the No. 1 front contacts of relay 203, the No. 2 back contacts of relay 204, conductor 206, the middle lower front contacts of relay H5, ring terminals and brushes of selectors |06 and |05, contacts of cams ||4 and H6. ring brush and terminal of the line nder |02, thence over the calling line loop, over the tip terminal and brush of the line finder |02, contacts of cams |20 and H3, tip brushes and terminals of selectors |05 and |06, middle upper front contacts of relay H5, conductor 205, the No. 8 back contacts of relay 204, the No. 7 front contacts of relay 203, the No. 6 back contacts of relay 204, to ground through the lower winding of relay 2|3. Relay 2 I3 upon operating over this circuit establishes a circuit from ground over its lower contacts, conductor 216, the No. 5 back contacts of relay 400 to battery through the Winding or" sloW-to-release relay 403, and at its upper contacts prepares the circuit or" relay 2|?. Relay 403 upon operating, locks in a circuit extending from battery through its winding, over the No. 5 back contacts of relay 400, the outer upper front contacts of relay 403, the No. 5 normal contacts of relay 40|, conductor 404, to ground at the No. 'Y-bacl; contacts of relay 2c4 and, at its inner upper front contacts, connects ground to conductor 405 and through the winding of relay 40| to battery. Relay 40| now operates, locking over its No. 5 alternate contacts and conductor 404 to ground at the No. '7 back contacts of relay 204; opens, at its No. 5 normal contacts the locking circuit for relay 433 just traced; completes the operating circuit of relay 2li' which may be traced from battery through its winding, over the upper contacts of relay 2|3, conductor 2|8, the No. 2 back contacts of relay 4055, the No. 1 front contacts of relay 40|, to ground at the back contacts of relay 40?; opens at its No. 4 back contacts the previously traced circuit for relay 5i2 which relay thereupon releases, and at its No. 2 contacts connects the sleeve lead SL over the No. 1 contacts of relay 201, conductor 22|, the No. 2 contacts of relay 40! to ground through the Winding of relay 407.

Seizure of request pronouncement circuit Relay 2|? upon operating, with relay ||5 operated to indicate a ten-cent toll call, establishes a circuit for trunk preference relay 624 (Fig. 6) which may be traced from battery over the lower contacts of relay 2|?, conductor 222, winding of relay 624 to ground.

Trunk connector relay 626 now operates in a circuit extending from grounded battery, through the winding of relay 626, inner upper iront contacts of preferance relay 624, through the back contacts and iirst upper armatures of all trunk preference relays, such as relay 025, back contacts of relay 627, to ground by way of the front contact and armature of normally energized slow-to-release relay 628. Relay 623 is operated in an obvious circuit. Relay 623 operates in parallel with the operated relay 626, its operating circuit including the upper front contacts of relay 624 and the associated upper back contacts of all other trunk preference relays such as relay 625, the back contacts of relay 621 and the front contacts of relay 628.

It will be observed that each trunk has access to a particular link (Fig. 6) by way of a trunk connector relay, such as relay 626, and each link circuit has access to all coin control circuits (Fig. 7) through a particular, so-called coin control connector relay such, for example, as relay 635. I

With relay 620 operated incident to the opera- 13 tion or" relay B24, relay G3i operates in a circuit extending from grounded battery, winding of relay tti, back contacts and lower armatures of either or both relays 63.2 and 633, to ground at the lower front contacts of relay 62 9.

Ground at the lower contacts of relay 629 is also extended over the upper back contact of relay 932, thence through the winding of relay 03d, to grounded battery, causing relay 934 to operate. With relay 631i operated, relay 635 operates in a circuit extending from grounded battery, winding of relay 635, inner upper armature and front contact ci relay 634 to ground at the inner front contacts of relay 629.

With relays 626 and 635 operated as described, the link L is interposed between the coin controlled pronouncement circuit (Fig. 7) and the leads extending from the trunk. When relay 52d operated, it locked to battery at the lower front contacts of relay 2|1 by way of conductor 222 and its own lower front contacts. Relay 035 at its innermost upper front contacts provides locking ground for relay 626 and at its middle lower armature locks itself to ground on conductor 134, which conductor is grounded when relay 'l hl operates, as will be described presently.

It will now be observed that with relay 2|1 operated and the trunk extended to the coin controlled pronouncement equipment by way of the link L, ground at the upper contacts of relay 2 1 is extended by way of the outerV lower front contacts of relay I (which relayV identifies a toll call requiring an initial charge of ten cents) to conductor 299, contact E39 of trunk connector relay 629, conductor 631 of link L, contact 639 of coin control connector relay B35, charge lead S39 which extends across the bottom of Figs. '1, 8 and 9 and terminates in contact 90| of the arc T3 of selector switch T, which switch also includes the terminal arcs TI, T2 and T4. Thus, in response to the seizure of the tandem trunk by way of the terminal appearance |01, which is allocated to calls whose initial toll charge is ten cents, the terminal 90| of arc T3 of the switch T is marked with ground potential from relay 2|1 by way of the charge lead 639. Y

The leads 090 and 64| of the link L extend the trunk leads 291 and 298 from the Nos. '7 and 2 armatures of relay 229 to corresponding conductors 10| and 102 which terminate at the middle and outermost lower armatures of relayv 103 associated with the pronouncement circuit.

The link lead 642 extends the sleeve conductor SL which, as hereinbefore described is extended to the winding of relay 401 by wayV of the No. 1 contacts of relay 20|, conductor 22|, and the No. 2 contacts of relay 40|, to the correspending lead 104.

The link leads 643 and 644 extend the trunk leads 29@ and 295 from upper and lower front contacts of relay 241 to the tip and ring terminals of jacks 101 and 108 in multiple. The link lead 945 connects the sleeves of jacks 101 and 198 to the lead 296 which is connected to the Nos. 2 and 4 armatures of relays 241 and l29 respectively. Y

The link lead 846 extends the operating winding of relay 110 to the conductor 648 which terminates at the lower front contact of overtime relay 59e. The link conductor 641 provides lockground for the operated trunk connector :relay 62S.

Initial response of request pronouncement circuit It will be observed that the ground which is -relay 113.

connected to the lead' 299 by virtue oi? the operation of both relays ||5 and 2|1 and extended to the terminal of arc T3 ofthe switch T by Way of charge lead 639, is also extended to battery through the winding of relay 1|2 by way of conductor 11|. Relay 1|2 accordingly operates in this circuit. At its lower front contacts relay 1I2 completes an obvious operating circuit for relay 103 which nds ground at the lower back contacts of relay 1|3.

Relay 103, in operating, locks under control of At its middle and outermost lower armatures, relay 103 extends the trunk conductors 10| and 102 to the output side of hybrid coil H. At its innermost lower armature and front contacts, relay 103 completes the following circuit: from battery, winding of relay 1M, upper back contacts and armature of relay 123, front contacts and innermost lower armature of relay 103, conductor 10d, corresponding front contacts of relay S35, link conductor 642 and corresponding front contacts of relay 626, sleeve conductor lSL, No. 1 contacts of relay 20|, conductor 221, No. 2 contacts of relay 40|, to ground through the winding of relay 401. Relay 1| 0 operates in this circuit and at its inner upper front contact applies ground to conductor 134 which serves to lock relay 695 over its middle lower front contact. This ground also causes relay 921 to operate in an obvious circuit which includes the innermost lower front con tact of relay 635. Relay 635 in operating operates relays, such as 692, of all other coin supervisory links to preclude the possibility of the same coin supervisory circuit from being connected to a trunk through one of the other links. The operation of relay B28 starts the process for releasing the 92d lock-out relay of the link. However, the ground is not fully removed from this path until relay 2|1 of the trunk circuit is released on the operation of relay 401. Relays 62S and 635, however, are locked operated. With relay 935 operated and relay 631i released, relay S32 operates over an obvious circuit and prevents the reseizure of this coin control circuit as previously described. Relay 821 locks by its lower front contact to all other links which are waiting for their call to belserved. Relay 621 is a gating relay which prevents new calls from being served in a link which has already had a call served, until the calls waiting in other links are served.

Relay 401 upon operating, at its inner upper contacts, establishes the circuit for relay 0d which relay operates and opens at its back contacts the previously traced circuit of relay 2|1 which now releases and removes ground at its upper armature and front contact from the conductor 299, which conductor as hereinbefore described is extended, by way of the link lead 631, to the charge conductor 639 which terminates in terminal 90|. of arc T3 of the switch T. It will be noted at this time that when relay 1|2 operated, as previously described, it connectedground to the lead 639 so that. the terminal 90| of arc T3 of switch T is maintained marked with ground potential after relay 2|1 releases.

Relay 228 now operates in a circuit which may be traced from grounded battery, lower winding of relay 1|5, back contact and innermost lower armature of relay 1|9, winding 1 |1 of hybrid coil H, front contact and middle lower armature of relay 103, conductor 10| and corresponding front contacts of relay 635, link lead E40 and corresponding front contacts of relay B26, conductor 231, No. '1 contacts of relay 229, winding of relay 228, No. 2 contacts of relay 229, conductor 298 and corresponding front contacts of relay 62E, link lead 541 and corresponding front contacts of relay 535, conductor 1112, outermost lower armature and iront contact of relay 123, winding 113 of hybrid coil I-l, second lower armature and bach contact of relay 115, to ground through the upper winding of relay 115. Relay 115 operates with relay 228 in this circuit.

Relay 432 upon operating, incident to the operation oi relay 461, as described, connects, at its outermost upper armature and front contact, a double frequency tone source 459 to the conductor 432 which, by Way of the No. '1 contacts of relay 229 is connected to conductor 251, thence to link lead G42, conductor 1111 to the hybrid coil H for a purpose which will appear from a later description; connects the winding of relay 491 over its No. 1 contacts and conductor 285 directly to the sleeve lead SL; and establishes a circuit for relay 412 which may be traced from battery through its winding, over conductor 413, the No. 6 back contacts of relay 229, contacts of relay 228, conductor 414, to ground over its No. 6 contacts.

Relay 412 now operates, locks in a circuit extending from battery through its winding, over conductor 4i3, the No. 6 back contacts of relay 222, conductor 415, its No. 4 contacts to ground over the No. 6 contacts of relay 428; at its No. 2 back contacts removes ground from conductor 412 extending to the line discharge network cornprising resistances 232, 231 and condenser 232; at its No. 3 contacts connects resistances 514 and 515 across the calling line in bridge of the windings of relay 2l3 in a circuit which may be traced from battery, through the upper winding of relay 213, the No. l back contacts of relay 234, the No. 3 back contacts of relay 229, conductor 233, the No. 6 back contacts of relay 411, the No. 2 back lcontacts of relay 418, the No. 3 contacts oi relay 412, conductor 419, serially through resistances` 514 and 515, conductor 422, the No. 6 back contacts of relay 254, to ground through the lower winding of relay 213; and connects ground over its No. contacts and co-nductor 42! to the :fixed contact of interruptor 555. As soon thereafter as the interruptor cam 55 causes the closure of its contacts, a circuit is completed from ground connected to conductor 421, thence over conductor 422, over the inner lower normal contacts and through the winding of counting relay 423 and resistance 425 to battery, and through the winding of relay 424 and resistance 425 to battery.

Relay 423 now operates, but the winding of relay 424 being shunted over its own No. 7 back contact does not operate so long as the contacts of interruptor 5135 are closed. Relay 423 upon operating, locks over its inner lower alternate contacts to ground over the No. "5 contacts of relay 412. Upon the next opening of the contacts of interrupter 5&5, the initial operating circuit of relay 423 is opened and relay 424 now operates in a circuit from battery through resistance 426, through its winding, over the inner lower alternate contacts of relay 423 to ground over the No. 5 contacts of relay 41'2. With relay 424 now operated, a shunt is estabilshed from conductor 419 over the No. 1 contacts of relay 424, and conductor 432 around resistance 514 thereby reducing the shunt across the calling line to a value of 50 ohms. With relays 423 and 424 both operated, the circuit of relay 5110 is established from battery, through its winding, conductor 515, the No. 3 contacts or relay 424, the lower contacts of relay 423 to ground at the No. 2 contacts of relay 411. Relay 500 upon operating, shunts resistance 515 over its upper contacts thereby reducing the resistance of the shunt across the calling line to zero.

Upon the next closure of the contacts associated with interruptor cam 535 ground is connected from conductor 421 over such contacts, conductor 422, the No. 7 front contacts of relay 424 to a point between the winding of relay 423 and resistance 425, whereupon the winding of relay 423 becomes shunted and relay 423 releases. The circuit of relay 530 is now opened at the lower contacts of relay 423 and relay 52d releases. With relay 423 released and relay 424 still operated, a circuit is established from battery through the winding of relay 2&4, over conductor 234, the inner upper back contacts o relay 423, the No. 6 contacts of relay 424, to ground applied to conductor 421 over the lower contacts of relay 421. Relay 264, operated, disconnects the windings of relay 213 from the calling line at its Nos. 1 and 6 back contacts while the line is still short-circuited; establishes a holding circuit for relay 403 extending from battery through its winding, over the No. 5 back Contact of relay 462, the No. 3 contacts of relay del, conductor 422 to ground at the No. 'l front contact of relay 254; transfers the tip and ring trunk conductors 2&5 and 203 at its Nos. 2 and 8 contacts from contacts of relay 223 to contacts of relay 22S in preparation of the return oi the initially deposited coin at the coin box lili ci the calling line, and establishes the operating cirouit for counting relay 413' which may be traced from battery through resistance 429, the winding and the No. 5 normal contacts of relay 413, the upper back contacts of relay 423, conductor 235, the No. 3 contacts of relay 254, conductor 236, the No. 4 contacts of relay 424, to ground at the No. 2 front contact of relay 412. The operating circuit for counting relay 411 is also prepared at this time from ground, thence as traced over the No. 5 normal contacts of relay 418 through the winding of relay 411 and resistance 432 to battery, but the winding of relay 411 is shunted at this time over its own No. 7 back contact so long as relay 424 remains operated and relay 411 does not therefore operate. Relay 418 upon operating now locks over a circuit from battery through resistance 422, its winding and No. 5 alternate contacts, conductor 235 and thence to ground as traced.

Vis connected from the source 511, over the No.

9 back contacts of charge relay 518, conductor 519, lower front contacts of relay 433, No. l. back contacts of relay 455, No. 1 back contacts of relay 411, No. 4 front contacts of relay 418, conductor 431, over the Nos. 1 and 8 bach contacts of relay 222 and the Nos. 2 and 8 front contacts of relay 254, thence as traced over the tip and ring conductors of the established connection through the magnet of coin box lill to ground over contacts closed thereat by the deposited coin. The coin box magnet is now energized in such a manner as to deposit the coin in the return chute where it may be recovered by the calling person.

Upon the second opening of the contacts associated with interruptor c am 505, the holding cir- 

